If by lease, you mean Contract Hire then all you normally get is a car and some tax every year.
Unless you do mega mileage don't bother with a maintenance contract as most new cars have service intervals of up to 20,000 miles so the extra you pay every month adds up to more than the one service you need in a 3 year contract.
b r is right about mileage, so long as the excess mileage charge isn't stupid (sub 10ppm) pay the adjustment at the end. If you end overestimate your mileage, however, you get nothing back and the lease company profits when they auction the car off.
Hope this helps.